Hi all, I couldn't find an S-Max section but I thought there's a chance that Focus, Mondeo and Kuga owners might have some clues as they all have the same engines.
This is a copy of the post I did on talkford. No luck on there, so thought I'd ask you good people:

Hi all, looking to see if anybody has been here with a charge light issue on a 2.5T?
It's a 2006 2.5T Titanium. Got bumped very lightly last year but there were issues with the insurance and it ended up being parked up for ages, unused. Battery went flat in this period, but recharged and seemed to hold it.

Since it was parked, the charge light came on. It wasn't immediately after the bump, so I don't believe that to be related (it was a parking ding, anyway).


Fault code given is P2502 - Charging System Voltage

Upon starting engine, light doesn't show for 30secs or so. In that time, the voltages seen by the PCM do not change, even when the light comes on. My guess is it's doing some kind of check and when it decides its not happy, it throws the light on.

Alternator was tested as dishing out 13.8v, despite the lamp being on. I renewed the alternator because I figured it was still possible the alt wasn't relaying the charge status back to the PCM (and I was out of ideas, otherwise).

New alternator didn't make a difference.

New battery fitted as I figured one or two cells might have died, and it was a few years old anyway. No difference (other than cranking voltages being better than they were).

Main earth terminal on body near battery is good.

Small connector to alternator shows 4v with ignition on - not sure what it's supposed to show.

Large cable connection is good. No corrosion.

With small connector unplugged, symptoms are exactly the same with exactly the same as above & with fault codes. The car behaves no differently whether the connector is plugged in, or not.

I'm guessing it's either PCM itself, or some kind of wiring fault. Are there any common areas to check?

Thanks